1. Field of the Invention
The present invention is based on a hand-held power tool.
2. Description of the Prior Art
Modern hand-held power tools are usually driven by electric universal motors, i.e. collector or brush motors. In them, current for the commutation is transmitted from the power cable via brushes to the rotor collector, which rotates during operation. The brushes are spatially fixed in the housing by means of brush holders. The brush holder is composed of a rectangular shaft that guides the rectangular brush axially. It is equipped with a spring that presses the brush toward the collector. The brush wears down at its contact point due to sliding friction against the collector and, due to the action of the spring, moves axially toward the collector in accordance with its wear-induced loss in length. It is thus possible to maintain the flow of current between the collector and brush.
Known hand-held power tool motors are provided with two brushes and therefore also have two brush holders that can be situated individually in the housing or can be supported opposite each other on a support plate that can be affixed in the housing.
There are known brush holders with blade terminals with which it is possible for example to electrically contact the brush cable, an electronic unit, the field coils, etc.
Relative to the motor axis, the spring is situated behind or next to the brush. Most often, a spiral/clock spring is used for this. In other designs, a compression spring is placed axially over the brush. This increases the overall length of the brush and the size of the motor housing due to the radial overlapping of the cover of the brush holder system. The resulting losses in convenience and safety must be taken into account when the motor housing is used as a handle.